Metallurgy



Patented Sept. 16, 1952 JM Q R I Marvin J. Uay, Niagara Falls, N." Y.,"as'si 'i1bi-Tc-* Guaranty Investment MontrealyQuebec, Canada, a corporation of Canada 1 Corporation Limited.

'No Drawing, Application September 19,1946, I I A I Serial N0. 617,447

This invention relate I I for an object the provision o'f certain improved reaction mixtures for use in'metallurgic'al methods or processes; More particularly, the invention contemplates the provision of certain improved reaction mixtures foruse in methods or "processes for the production of! cast iron. A

specific object of the invention is-to provide an improved reactionsmixturesuitable:for .use in producing. high-,strength-icast' iron. Alfurther t o metallurgy and has object of thewinventionisrito provide improved exothermic, reaction mixtures suitablefor use in the production sof h1'gh=strengthcast. iron.

The reactionimixtures ofrthe invention maybe employed 'in any suitable-processes; but they are particularly useful for treating cast iron] Cast iron can be treatedwhile in themolten state with an exothermic reaction. mixture of. the invention comprising. silicon, strontium .and a nitratejradical tojproduce cast iron products to pass 5 a" IOU-mesh screen the, agglomerates or briquets.

416mm. (crea -2r)- ccniunction with any one ormore of thenitrates of strontiumbarium, calcium and magnesium,

Exothermic reaction mixtures of the invention preferably contain ferrosilicon as the source of silicon, and they preferably are formed by grind- .ing together the components; to form mixtures of particlesmost orall of whichfaresmallenough I I I I Grindingtogether of the components results in thorough and intimate mixing which is conducive to effective and complete reaction; The reaction mixtures may "be employed in the form of' lodse-powde1-s or in the form of agglomerate's or briquets. Any suitable bonding agent may be employed in forming ii hfi SQ nitrate i employed; may function as the bondhaving improved mechanical or physical properties. 1 Thus, "for example, it.- 1 has (been found that byzr'eactin'g with. 51101152, ;reaction-,:.mixture molten cast iron, such as cupolaiuironi'andblast I furnace iron; containing about .two and seventyflve vhundredths percentw:(2.-'7.5%) to three and twenty-five; hundredths-zpercent (-3.25%) :of carbon and silicon in amount. less thanthat required 1 ior highrstrengthgcast iron, .cast'. iron,

products having improvedtransver'se, tensile, deflection, impact, hardness: and other properties can be produced. The reaction mixtures of the invention aregparticularly useful in methods or processes for producing gray cast iron. The use of exothermic reaction mixtures of the invention for treating cast iron the depth of chill. III

In carrying out a method or processemploying a reaction mixture of the invention," molten cast iron from any suitable source" is reacted ina ladle, for; example, with an exothermic reactionrinixture in; amount sufficient tomodiiy the I mechanical or physical properties or ;characteristic's of the cast iron by increasing the silicon content without altering substantially the composition of the cast iron with respect to total carbon.

In carrying out a method or process employing a reaction mixture of the invention, I may employ an exothermic reactionmixture comprising a nitrate of any metal of the group consisting of strontium, barium, calcium and magnesium, or I may employ an exothermic reaction mixture comprising a compound of strontium, a nitrate of another metal and silicon. Two or more nitrates may be employed in a reaction mixture if desired. Sodium nitrate may be employed in has little or no effect on ing agen'tl Thus, for example, a,finlyl{divided mixture comprising sodium nitrate may be moistened with water-in amount'by weight equal to weight'bf i the mixture; molded, heated to drive ofi wa'teraiid melt the sodiumjni tra'te and cooled to' permit solidification of the sodium nitrate in place. Thefs'olidified sqdmnrmaa e is intimately associated-with the' otliercoinponents and functions as the bonding agent. 5

The components of'areaction mixture of the invention are so proportioned as to provide silicon in excess: of the-amountwhich can be oxidized by all of the nitrate and any other reducible compound which. maybe present. The excess silicon enters the molten castiron', increasing the silicon concentration and causing a graphitizing .e

ect on thecarbon contained therein. Nitrate and silicon for oxidationby the nitrate preferably are employed in amounts such that, by reaction,

sufiicient heat is generated to melt the excess silicon, so that the excess silicon enters the m te a iqi onin the m t n s t a d b c m s ..quicl ;ly and thorou hl dispersed therein.

he followingi examples: illustrate reaction {m tures of, theinventionz; 1"

mamas uireproportions of the compoparts by Weight.)

(In the various examples action mixtures, the nents are set forth in Strontium nitrate-SNNOa): 16.6

' Strontium nitrate-48r- Ma ta "wt-re a- -'I'he'-rbas'c iron used in the-tests [F results set forth above we'r: obtaineelwas a- ;1 'wsilicon (.70 :to .8096 Si')*.ciipola castfircn-noi mally made according to standai-d cmmerfi fil $39 iti'act te.s,

2,610,911 1 3 4 7 III 7 XIII Ferrosilicon (75% Si) 81.7 Strontium nitrateSr(NOa)a 1 -3 lhcmicalAnalysis Mechanical Properties w i i 5 i gi n r R r fl fi iflfifit Slime-J -Y-';.-i'-.-i,;..-'-i+. 8 0, 7 *1} ,ffli iis' Defin -5 a 11 Im- Strontiiimnitra'te-QSriNOs)z; i 18.0 6 fi1 $518M i Pact Silica flour 2.0 v I V v I Example vm. 3.08 .42 1.72 3,625 363 51,750 62.9 I W SD m m meter 2-22 1-2? 222 an 22-: Ferrosilicon o 1. '1 1 n r E2353? 1": 5 132 215% 1 :iii 3:383 22:; Strontium nitrate-SrfiN n H VI was similar to that employed Ferrosilicon (15% Si) -i 80.0 in the tests for-"which results are set rorth in Barium mtr'aapeamooh nwwm ago 15 nxarnnlemiabove.

' VII I F? t t t b I reac ion mix ure sui a le for use in treatgi i 5 7; fia

ing -n'iolten cast iron which comprises (1) silicon. ron um n z "7*" (2) one or more chemically combined elements at ma ma camistmzeot calcium; s..tronti.um. and: ma nesium; and (39 "a; chemical components: of; the-re- I action mixtmevbeinsi ntsuch compositions and bcinesnreeentriirauehmnortionsasmhecapable or exathermicallr upon. contact with moltenanast'cimntodeccmposethe nitrate radical withbxidatdon i 2; A zeactionamixtnrezsiiitable for, use in :treat-' ing molten castf irlim-comprisingr silicon and calciumpitrate. componentszoiithe'reaction mixture being cf-wsuchi-comnositions and being present in such.propcrtionaastozbezcapable oi'reacting exo- I y thermicailiy: upon-contact witl r molten cast iron to Qecc'irripdee-the-caiciuninitrate with oxidation oi siliconr a. Areaction mixtnresnitabie ror ase-1n treating'i moltenv easmmn, comprisingsilicon and -barium nitrate; components of the; reaction mixture' being nf'siicir compositions and being present-4n siicir proportions -asrto be capable of reacting-excthermiealh upon contact with molten cast iron- :to decompose the-barium nitrate with 'ox idaationwoiisi-iicon;

' 4; mrcactlon'mixtiire'sui- I i-ng molten-castircnicomprising silicon and mag! nesiiim mime; components:- of thereaction mix-- tur b'e'ing-o! sucii compositionsand being present ir rsuch proporticnslasto becapable of reactingfeiiothermicaliy upon contact with molten cast iron to decompose=the magnesium nitrate with ionaaumer nmom v J; DY;

1 itni mrnnonscrrnnz The following references amorrecord ifnlthe fiie of this patent: I

; umriimnsfmresrarems.

his termeiii-neat v 

1. A REACTION MIXTURE SUITABLE FOR USE IN TREATING MOLTEN CAST IRON WHICH COMPRISES (1) SILICON. (2) ONE OR MORE CHEMICALLY COMBINED ELEMENTS OF THE GROUP CONSISTING OF CALCIUM, STRONTIUM. BARIUM AND MAGNESIUM AND (3) A CHEMICALLY COMBINED NITRATE RADICAL, COMPONENTS OF THE REACTION MIXTURE BEING OF SUCH COMPOSITIONS AND BEING PRESENT IN SUCH PROPORTIONS AS TO BE CAPABLE OF REACTING EXOTHERMICALLY UPON CONTACT WITH MOLTEN CAST IRON TO DECOMPOSE THE NITRATE RADICAL WITH OXIDATION OF SILICON. 